Sheep in this sense is not referring to sheep the animal, but to a concept of the word that describes the bandwagon/mob/slave mentality. When a person is doing a sheeptivity, they are doing something that is confined within the limits of his/her social thought. As a result, they are doing activities that are highly predictable. So basically, appropriating or conforming to cultural rituals could be referred to as sheeptivities.

Sally: That’s such a sheeptivity Ted…I mean Ned…Everyone does it, and everyone does it all the time. We’ve been dating for only 14 days, given that time span, shouldn’t we be doing extraordinary things right now?